Average Slope

[nicethugbert]

How do I get some average slope on a map?

I set Altitude Range to max and made maps with Scale of Features set from 0 to 100. They all appear to be fluctuations around 0 meters.

What am I doing wrong? Is my sense of scale off?

The maps were all 8192x8192 pixels with 0.625 Horizontal Scale.

[Aaron]

Hi nicethugbert,

I apologise for the delay in my reply.

I hope you don't mind me saying, but this seems to be a somewhat unusual request. Do you want to set some average slope of, for example, 20 degrees, and have L3DT rescale the terrain accordingly?

...They all appear to be fluctuations around 0 meters...

Yes, they will be unless you also set the 'average altitude' slider. This slider sets the mid-range height of your terrain, whereas 'altitude range' sets the difference between the highest to lowest. FYI the 'scale of features' slider sets the horizontal size (in pixels) of the noise used to create the design map, and also influences the limits of the 'altitude range' slider.

Cheers,
Aaron.

[nicethugbert]

I want to set the Yaw, Pitch, and Roll of the design map. I don't know about rescaling. I'd have to understand L3DT better for that.

I do not see this as unusual. There are plenty of examples in nature.

[Aaron]

Hi Nicethugbert,

Okay, I think I understand your request now.

Are you familiar with differential calculus? Slope is the first derivative of the heightfield, so height and slope are not independent variables; you can set one or the other, but not both. By setting the heights in the design map, you have (indirectly, but necessarily) set the slope.

Could I modify L3DT to allow you to set the slope at a point? Perhaps, but I would also have to then take away control of the heights, since L3DT would then need to calculate the heights that correspond to your set of slopes using numerical integration. Gaining direct control over slopes at the cost of direct control over heights seems like a poor deal. I will not make this change.

Best regards,
Aaron.

[nicethugbert]

I don't really understand very well what you are saying. I'm as familiar with calculus as the average person is. I find it clumsy. I never use it.

I'm envisioning a plane in 3D space. I know that the Yaw, Pitch, Roll equations on a plane are continuous and the DM is not. So, The plane is discretized, like a DM. Then I imagine heights being made by whatever way the DM normally does this. The two sets of heights are added together. I don't know how this affects the rest of the DM parameters. I'm guessing the addition happens first so it influences the rest of the process properly.

IIRC, L3DT makes a HF by expanding the DM and filling in the gaps with a lot of cones, then further processing. But, since this is happening on the DM map. The orientation of the cones is not an issue. The HF process just sees yet another DM.

The tools available now are zeoscript, zeograph, extensions, and I'm guessing overlays. I don't know how to use these or if they are capable of what I am imagining.

I can make a discretized tilted plane in a spreadsheet, somehow. Then I can import it as a DM by using L3DTio_CSV. But, then I can't use Average Altitude, Altitude Range, and Scale of Features. Scale of features would be really useful here.

I wouldn't mind seeing scale of features allow for wider features.

[Aaron]

Hi Nicethugbert,

I apologise for the delay in my reply.

As far as I can tell from your description, what you describe cannot be implemented in a general sense. However, ZeoGraph and ZeoScript are now sufficiently capable to allow you to attempt such an algorithm, as you can get and set design map and heightfield pixel values, perform all necessary arithmetic and trigonometric operations, iterate through the map using loops, etc. It may not be as fast as fast as a compiled plugin, but if you can generate a complete script / graph that you're happy with, I'll be happy to translate it into a plugin for you.

Best regards,
Aaron.